<?php
// This file is part of BOINC.
// http://boinc.berkeley.edu
// Copyright (C) 2008 University of California
//
// BOINC is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License
// as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// BOINC is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with BOINC. If not, see <http://www.gnu.org/licenses/>. 
//
// This file was modified by contributors of "BOINC Web Tweak" project.

// Bolt scheduler.
// GET args:
//   course_id: course ID
//   action: see commands below

require_once("../inc/bolt.inc");
require_once("../inc/bolt_sched.inc");
require_once("../inc/bolt_db.inc");
require_once("../inc/bolt_ex.inc");
require_once("../inc/bolt_util.inc");
require_once("../inc/util.inc");

function debug_show_state($state, $tag) {
	global $user;
	global $refresh;
	if ($user->bolt->flags&BOLT_FLAGS_DEBUG) {
		echo "$tag state: <pre>"; print_r($state); echo "</pre>\n";
		if ($refresh) {
			echo "<p>Refresh ID: $refresh->id<p>";
		}
		echo "<hr>\n";
	}
}
function debug_show_item($item) {
	global $user;
	if ($user->bolt->flags&BOLT_FLAGS_DEBUG) {
		echo "Item:<pre>"; print_r($item); echo "</pre>\n";
		echo "<hr>\n";
	}
}

function update_info() {
	global $user;
	$sex = get_int('sex');
	$birth_year = get_int('birth_year');
	$user->bolt->update("sex=$sex, birth_year=$birth_year");
}

// The user clicked something on a page.
// Look up the view record (the ID is in the URL) and update it
// with the action and the time.
// Return the record.
//
function finalize_view($view_id, $action) {
	global $user;
	if (!$view_id) return null;
	$view = BoltView::lookup_id($view_id);
	if (!$view) {
		error_page("no view");
	}
	if ($view->user_id != $user->id) {
		error_page("wrong user");
	}
	if (!$view->end_time) {
		$now = time();
		$view->update("end_time=$now, action=$action");
	}
	return $view;
}

function default_mode($item) {
	return $item->is_exercise()?BOLT_MODE_SHOW:BOLT_MODE_LESSON;
}

// A page is being shown to the user; make a record of it
//
function create_view($iter, $mode, $prev_view_id) {
	global $user;
	global $course;

	$now = time();
	$item = $iter->item;
	if (!$item) {
		$item = null;
		$item->name = '--end--';
	}
	$state = $iter->encode_state();
	debug_show_state($iter->state, "Ending");
	return BoltView::insert("(user_id, course_id, item_name, start_time, mode, state, fraction_done, prev_view_id) values ($user->id, $course->id, '$item->name', $now, $mode, '$state', $iter->frac_done, $prev_view_id)");
}

function page_header() {
	global $course;
	echo "<html><head>
		<title>$course->name</title>
		<link rel=stylesheet type=text/css href=bolt.css>
		</head><body>
	";
	if (function_exists('bolt_header')) bolt_header();
}

function page_footer() {
	if (function_exists('bolt_footer')) bolt_footer();
	echo "</body></html>";
}

// show a page saying the course has been completed
//
function show_finished_page($view_id, $prev_view_id) {
	global $course;
	global $url_args;

	page_header("Course completed");
	if ($course->bossa_app_id) {
		require_once("../inc/bossa_db.inc");
		$app = BossaApp::lookup_id($course->bossa_app_id);
		echo "
			Congratulations - you have completed the training for $course->name.
			<p>
			You may now
			<a href=bossa_get_job.php?bossa_app_id=$course->bossa_app_id>do work</a>.
		";
	} else {
		echo "Congratulations - you have completed this course.";
		$links[] = "<a href=bolt_sched.php?$url_args&action=prev&view_id=$view_id><img src=img/prev.gif></a>";
		$up_link = "<a href=bolt_sched.php?$url_args&action=course_home&view_id=$view_id>Course home page</a>";
		show_nav($links, $up_link, $view_id);
	}
	page_footer();
}

function show_refresh_finished() {
	page_header("Refresh completed");
	echo "<a href=bolt.php>Return to courses</a>";
	page_footer();
}

function show_nav($links, $up_link, $view_id) {
	global $course;

	echo "<p><center>
		<table width=60%><tr>
	";
	foreach ($links as $link) {
		echo "<td align=center>$link</td>\n";
	}
	echo "</tr></table> </center>
		<hr>
		<br>
		<form action=bolt_sched.php>
		<input type=hidden name=course_id value=$course->id>
		<input type=hidden name=action value=question>
		<input type=hidden name=view_id value=$view_id>
		<textarea name=question cols=60 onfocus=\"this.value=''\">Enter question or comment here</textarea>
		<br>
		<input type=submit value=Submit>
		</form>
		<p>
		$up_link
	";
}

// show an item (lesson, exercise, answer page)
//
function show_item($iter, $view_id, $prev_view_id, $mode, $repeat=null) {
	global $user;
	global $course;
	global $bolt_ex;
	global $refresh;
	global $url_args;

	$item = $iter->item;
	page_header();
	$bolt_query_string = $item->query_string;

	$links = array();
	if ($prev_view_id) {
		$links[] = "<a href=bolt_sched.php?$url_args&action=prev&view_id=$view_id><img src=img/prev.gif></a>";
	}

	$next = "<a href=bolt_sched.php?$url_args&action=next&view_id=$view_id><img src=img/next.gif border=0></a>";

	if ($item->is_exercise()) {
		$bolt_ex->mode = $mode;
		$bolt_ex->index = 0;
		switch ($mode) {
		case BOLT_MODE_SHOW:
			echo "
				<form action=bolt_sched.php>
				<input type=hidden name=view_id value=$view_id>
				<input type=hidden name=course_id value=$course->id>
				<input type=hidden name=action value=answer>
			";
			if ($refresh) {
				echo "
					<input type=hidden name=refresh_id value=$refresh->id>
				";
			}
			srand($view_id);
			require($item->filename);
			if (function_exists('bolt_divide')) bolt_divide();
			$next = "<input type=image src=img/next.gif value=OK></form>";
			break;
		case BOLT_MODE_ANSWER:
			require($item->filename);
			if (function_exists('bolt_divide')) bolt_divide();
			$score_pct = number_format($bolt_ex->score*100);
			echo "Score: $score_pct%";
			break;
		}
	} else {
		require_once($item->filename);
		if (function_exists('bolt_divide')) bolt_divide();
	}

	if ($repeat) {
		$avg = number_format($repeat->avg_score*100, 0);
		echo "<p>Score on this exercise set: $avg%";
		if ($repeat->flags & REVIEW) {
			//echo "<pre>";
			//print_r($repeat);
			//echo "</pre>";
			$name = urlencode($repeat->unit->name);
			$r = "<a href=bolt_sched.php?$url_args&action=review&view_id=$view_id&unit_name=$name>Review, then repeat exercises</a>";
			$links[] = $r;
		}
		if ($repeat->flags & REPEAT) {
			$r = "<a href=bolt_sched.php?$url_args&action=repeat&view_id=$view_id>Repeat exercises</a>";
			$links[] = $r;
		}
		if ($repeat->flags & NEXT) {
			$links[] = $next;
		}
	} else {
		$links[] = $next;
	}

	$up_link = "<a href=bolt_sched.php?$url_args&action=course_home&view_id=$view_id>Course home page</a>";
	show_nav($links, $up_link, $view_id);

	page_footer();

	if ($refresh) {
		$refresh->update("last_view_id=$view_id");
	} else {
		$e = new BoltEnrollment();
		$e->user_id = $user->id;
		$e->course_id = $course->id;
		$e->update("last_view_id=$view_id");
	}
}

// Show the student the results of an old exercise; no navigation items
//
function show_answer_page($iter, $score) {
	global $bolt_ex;

	$bolt_ex->mode = BOLT_MODE_ANSWER;
	$bolt_ex->index = 0;

	$item = $iter->item;
	page_header();
	$bolt_query_string = $item->query_string;
	require_once($item->filename);
	if (function_exists('bolt_divide')) bolt_divide();
	$score_pct = number_format($score*100);
	echo "Score: $score_pct%";
	page_footer();
}

function start_course() {
	global $user;
	global $course;
	global $course_doc;

	BoltEnrollment::delete($user->id, $course->id);
	$iter = new BoltIter($course_doc);
	$iter->at();

	$now = time();
	$mode = default_mode($iter->item);
	$view_id = create_view($iter, $mode, 0);
	BoltEnrollment::insert("(create_time, user_id, course_id, last_view_id) values ($now, $user->id, $course->id, $view_id)");
	show_item($iter, $view_id, 0, $mode);
}

function start_refresh() {
	global $course_doc;
	global $refresh;

	$xset_result = BoltXsetResult::lookup_id($refresh->xset_result_id);
	if (!$xset_result) error_page("Exercise set result not found");
	$view = BoltView::lookup_id($xset_result->view_id);
	if (!$view) error_page("view not found");
	$iter = new BoltIter($course_doc);
	$iter->decode_state($view->state);
	$iter->at();
	$xset = $iter->xset;
	if (!$xset || $xset->name != $xset_result->name) {
		error_page("missing exercise set");
	}
	$xset->restart($iter);
	$iter->at();
	$mode = default_mode($iter->item);
	$view_id = create_view($iter, $mode, 0);
	show_item($iter, $view_id, 0, $mode);
}

function show_next($iter, $view) {
	global $refresh, $user, $course;
	$iter->next();

	if ($refresh) {
		$iter->at();
		if (!$iter->xset) {
			// if we're doing a refresh and are no longer in an xset,
			// we must have finished the refresh
			//
			show_refresh_finished();
			$refresh->update('count=count+1');
			break;
		}
	}

	if ($iter->item) {
		$state = $iter->encode_state();
		$mode = default_mode($iter->item);
		$view_id = create_view($iter, $mode, $view->id);
		show_item($iter, $view_id, $view->id, $mode);
	} else {
		// course finished
		$iter->frac_done = 1;
		$fin_view_id = create_view($iter, BOLT_MODE_FINISHED, $view->id);
		$e = new BoltEnrollment();
		$e->user_id = $user->id;
		$e->course_id = $course->id;
		$e->update("last_view_id=$fin_view_id");
		show_finished_page($fin_view_id, $view->id);
	}
}

$user = get_logged_in_user();
BoltUser::lookup($user);
$course_id = get_int('course_id');
$refresh_id = get_int('refresh_id', true);
$refresh = null;
$url_args = "course_id=$course_id";
if ($refresh_id) {
	$refresh = BoltRefreshRec::lookup_id($refresh_id);
	if (!$refresh) error_page("No such refresh");
	if ($refresh->user_id != $user->id) error_page("Wrong user");
	if ($refresh->course_id != $course_id) error_page("Wrong course");
	$url_args .= "&refresh_id=$refresh_id";
}
$course = BoltCourse::lookup_id($course_id);
if (!$course) {
	error_page("no such course");
}
$view_id = get_int('view_id', true);
$action = get_str('action', true);
$course_doc = require_once($course->doc_file());

switch ($action) {
case 'start':
	if (info_incomplete($user)) {
		request_info($user, $course);
		exit();
	}
	if ($refresh) {
		start_refresh();
		exit();
	}
	$e = BoltEnrollment::lookup($user->id, $course_id);
	if ($e) {
		page_header();
		echo "You are already enrolled in $course->name.
			<p>
			Are you sure you want to start over from the beginning?
			<p>
		";
		show_button(
			"bolt_sched.php?action=start_confirm&$url_args",
			"Yes",
			"Start this course from the beginning"
		);
		show_button(
			"bolt_sched.php?action=resume&$url_args",
			"Resume",
			"Resume course from current position"
		);
		page_footer();
		exit();
	}
	// fall through
case 'start_confirm':
	start_course();
	break;
case 'update_info':
	update_info();
	start_course();
	break;
case 'prev':
	$view = finalize_view($view_id, BOLT_ACTION_PREV);
	debug_show_state(unserialize($view->state), "Initial");
	if ($view->prev_view_id) {
		$view = BoltView::lookup_id($view->prev_view_id);
		$iter = new BoltIter($course_doc);
		$iter->decode_state($view->state);
		$iter->at();
		$mode = $view->mode;
		if ($mode == BOLT_MODE_ANSWER) {
			$v2 = BoltView::lookup_id($view->prev_view_id);
			$result = BoltResult::lookup_id($v2->result_id);
			srand($v2->id);
			$bolt_ex->score = $result->score;
			$bolt_ex->query_string = $result->response;
		}
		$view_id = create_view($iter, $mode, $view->prev_view_id);
		show_item($iter, $view_id, $view->prev_view_id, $mode);
	} else {
		error_page("At start of course");
	}
	break;
case 'next':			// "next" button in lesson or exercise answer page
	$view = finalize_view($view_id, BOLT_ACTION_NEXT);
	debug_show_state(unserialize($view->state), "Initial");

	$iter = new BoltIter($course_doc);
	$iter->decode_state($view->state);
	show_next($iter, $view);
	break;
case 'answer':		  // submit answer in exercise
	$view = finalize_view($view_id, BOLT_ACTION_SUBMIT);
	debug_show_state(unserialize($view->state), "Initial");
	$iter = new BoltIter($course_doc);
	$iter->decode_state($view->state);
	$iter->at();

	debug_show_item($iter->item);
	$item = $iter->item;
	if (!$item->is_exercise()) {
		print_r($item);
		error_page("expected an exercise");
	}
	if ($view->item_name != $item->name) {
		error_page("unexpected name");
	}

	// compute the score

	$bolt_ex->query_string = $_SERVER['QUERY_STRING'];
	$bolt_ex->mode = BOLT_MODE_SCORE;
	$bolt_ex->index = 0;
	$bolt_ex->score = 0;
	$bolt_query_string = $item->query_string;
	srand($view_id);
	ob_start();	 // buffer output to avoid showing exercise text
	require($item->filename);
	ob_end_clean();

	$bolt_ex->score /= $bolt_ex->index;

	if ($item->callback) {
		call_user_func(
			$item->callback, $bolt_ex->score, $bolt_ex->query_string
		);
	}

	// make a record of the result

	$qs = BoltDb::escape_string($_SERVER['QUERY_STRING']);
	$now = time();
	$result_id = BoltResult::insert(
		"(create_time, user_id, course_id, view_id, item_name, score, response)
		values ($now, $user->id, $course->id, $view->id, '$view->item_name', $bolt_ex->score, '$qs')"
	);
	$view->update("result_id=$result_id");

	// If this is part of an exercise set, call its callback function
	//
	$repeat = null;
	$xset = $iter->xset;
	if ($xset) {
		$is_last = $xset->xset_record_score(
			$iter, $bolt_ex->score, $view->id, $avg_score, $repeat
		);
		if ($repeat) $repeat->avg_score = $avg_score;
		if ($is_last) {
			// if the exercise set if finished, make or update DB records
			//
			if ($xset->callback) {
				call_user_func($xset->callback, $avg_score);
			}
			$now = time();
			$id = BoltXsetResult::insert("(create_time, user_id, course_id, name, score, view_id) values ($now, $user->id, $course->id, '$xset->name', $avg_score, $view_id)");
			$refresh_intervals = $xset->refresh;
			if ($refresh_intervals) {
				$refresh_rec = BoltRefreshRec::lookup(
					"user_id=$user->id and course_id=$course->id and name='$xset->name'"
				);
				if ($refresh_rec) {
					$count = $refresh_rec->count;
					$n = count($refresh_intervals->intervals);
					if ($count >= $n) {
						$count = $n - 1;
					}
					$due_time = time() + $refresh_intervals->intervals[$count]*86400;
					$refresh_rec->update("create_time=$now, xset_result_id=$id, due_time=$due_time");
				} else {
					$due_time = time() + $refresh_intervals->intervals[0]*86400;
					BoltRefreshRec::insert(
						"(user_id, course_id, name, create_time, xset_result_id, due_time, count) values ($user->id, $course->id, '$xset->name', $now, $id, $due_time, 0)"
					);
				}
			}
		}
	}

	// show the answer page

	if ($item->has_answer_page) {
		srand($view_id);
		$view_id = create_view($iter, BOLT_MODE_ANSWER, $view->id);
		show_item($iter, $view_id, $view->id, BOLT_MODE_ANSWER, $repeat);
	} else {
		show_next($iter, $view);
	}
	break;
case 'answer_page':
	$view = BoltView::lookup_id($view_id);
	$iter = new BoltIter($course_doc);
	$iter->decode_state($view->state);
	$iter->at();
	if ($iter->item->name != $view->item_name) {
		error_page("Exercise no longer exists in course");
	}
	$result = BoltResult::lookup_id($view->result_id);
	srand($view_id);
	$bolt_ex->query_string = $result->response;
	show_answer_page($iter, $result->score);
	break;
case 'course_home':
	$view = finalize_view($view_id, BOLT_ACTION_COURSE_HOME);
	Header("Location: bolt.php");
	break;
case 'review':
	// user chose to do review then repeat an exercise set
	//
	$view = finalize_view($view_id, BOLT_ACTION_REVIEW);
	debug_show_state(unserialize($view->state), "Initial");
	$iter = new BoltIter($course_doc);
	$iter->decode_state($view->state);
	$iter->at();
	if (!$iter->xset) {
		echo "NO XSET"; exit;
	}
	$xset = $iter->xset;
	$unit_name = get_str('unit_name');
	$found = $xset->start_review($iter, $unit_name);
	if (!$found) {
		echo "REVIEW UNIT MISSING"; exit;
	}
	$iter->at();
	$mode = default_mode($iter->item);
	$view_id = create_view($iter, $mode, $view->id);
	show_item($iter, $view_id, $view->id, $mode);
	break;
case 'repeat':
	// user chose to repeat an exercise set
	//
	$view = finalize_view($view_id, BOLT_ACTION_REPEAT);
	debug_show_state(unserialize($view->state), "Initial");
	$iter = new BoltIter($course_doc);
	$iter->decode_state($view->state);
	$iter->at();
	if (!$iter->xset) {
		echo "NO XSET"; exit;
	}
	$xset = $iter->xset;
	$xset->restart($iter);
	$iter->at();
	$mode = default_mode($iter->item);
	$view_id = create_view($iter, $mode, $view->id);
	show_item($iter, $view_id, $view->id, $mode);
	break;
case 'resume':
	// user chose to resume a course or refresh
	//
	if ($refresh) {
		if ($refresh->last_view_id) {
			$view = BoltView::lookup_id($refresh->last_view_id);
		} else {
			start_refresh();
			exit();
		}
	} else {
		$view = null;
		$e = BoltEnrollment::lookup($user->id, $course_id);
		if ($e) {
			$view = BoltView::lookup_id($e->last_view_id);
		}
		if (!$view) {
			start_course();
			break;
		}
	}
	if ($view->mode == BOLT_MODE_FINISHED) {
		show_finished_page($view->id, $view->prev_view_id);
		break;
	}
	$iter = new BoltIter($course_doc);
	$iter->decode_state($view->state);
	$iter->at();
	$mode = $view->mode;
	if ($view->item_name == $iter->item->name && ($mode == BOLT_MODE_ANSWER)) {
		// if we're returning to an answer page,
		// we need to look up the user's responses and the score.
		//
		$view_orig = BoltView::lookup_id($view->prev_view_id);
		$result = BoltResult::lookup_id($view_orig->result_id);
		srand($view_orig->id);
		$bolt_ex->query_string = $result->response;
		$bolt_ex->score = $result->score;
		$bolt_ex->index = 0;
		$view_id = create_view($iter, $mode, $view_orig->id);
		show_item($iter, $view_id, $view_orig->id, $mode);
	} else {
		$view_id = create_view($iter, $mode, $view->id);
		show_item($iter, $view_id, $view->id, $mode);
	}
	break;
case 'question':
	$view = finalize_view($view_id, BOLT_ACTION_QUESTION);
	debug_show_state(unserialize($view->state), "Initial");
	$now = time();
	$question = BoltDb::escape_string(get_str('question'));
	BoltQuestion::insert("(create_time, user_id, course_id, name, mode, question, state) values ($now, $user->id, $course->id, '$view->item_name', $view->mode, '$question', 0)");
	page_header();
	echo "
		Thanks; we have recorded your question.
		Questions help us improve this course.
		We aren't able to individually respond to all questions.
		Responses are delivered as private messages.
		<p>
		<a href=bolt_sched.php?$url_args&action=resume>Resume course</a>
	";
	page_footer();
	break;
default:
	error_page("unknown action: $action");
}

?>
